Central-station call system for telephone-lines.



W. E. BUTLER.

CENTRAL STATION CALL SYSTEM FOR TELEPHONE LINES.

APPLICATION FILED FEB.15,1909.

977,067. 7 Patented N0vl29, 1910.

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CENTRAL STATION CALL SYSTEM FOR TELEPHONE LINES.

APPLIOATION FILED IEEJS, 1909.

Patented Nov. '29, 1910.

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OENTRAL STATION CALL SYSTEM FOR TELEPHONE LINES.

APPLICATION FILED FEB.15,1909. 977,067.

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APPLICATION FILED FEB.15, 1909.

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CENTRAL STATION CALL SYSTEM EOE TELEPHONE LINES.

APPLICATION FILED FBBJE, 1909.

977,067. E Patented N0v.'29,1910.

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CENTRAL STATION CALL SYSTEM FOR TELEPHONE LINES.

APPLICATION FILED FEB-15, 1909.

Patented Nov. 29, 1910.

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WILLIAM E. BUTLER,. OF DAVID CITY, NEBRASKA.

CENTRAL-STATION CALL SYSTEM FOR TELEPHONE-LINES.

Specification of Letters Patent.

Patented Nov. 29, 1910.

Application filed February 15, 1909. Serial No. 478,003.

To all whom it may concern:

Be it known that l, \ViLLLUt E. BUTLER, a citizen of the United States,residing at David City. in the county of Butler and State of Nebraska,have invented a new and useful Central-Qtation Call System forTelephone-Lines, of which the following is a specification.

This invention has reference to improvements in central station callsystems for telephone lines. and is designed to provide a centralstation ringing equipment where by currents having ditlerentcharacteristics may be sent to line for the selective operation ofmulti-party lines and whereby a much clearer ringing of the bell isobtained than in prior designs, and the system also provides meanswhereby batteries or like sources of constant current may be utilized atthe central station, and the cun rent furnished thereby may be convertedinto alternating current and sent to line while at the same time theswitch board is kept free from ringing induction and the kick-back intothe batteries is prevented.

The invention will be best understood from a consideration of thefollowing detail description taken in connection with the accompanyingdrawings forming a part of this specification in which drawings,

Figure 1 is a diagram whereby positive, negative or alternating currentmay be sent to line at the will of the operator. Fig. 2 is an elevationwith parts in section of an electric motor and a circuit controllingcommutator especially adapted for use in connection with the systemsherein shown. Fig. 3 is a side elevation of the commutator end of themotor showing a somewhat modified form of commutator. Fig. 4 is a bottomplan view of the commutator shown in Fig. Fig. 5 is a diagram showing acommon battery ringing machine circuit for alternating systems. Fig. (5is a diagram of a more complex or extended system than shown in Fig. 5.Fig. 7 a diagram showing a still further development of the circuitshown in Fig. 5. Fig. 8 is a diagram of a ringing machine circuit forcommon battery alternating and pulsating systems. Fig. l) is a diagramof a harmonic ringing machine. Fig. 10 is a view of a commutator of thedisk type for the harmonic ringing machine of Fig. 9.

Referring first to Fig. 2 there is shown a motor especially adaptedfor-the purposes of the present invention, although this does notpreclude the use of other motors.

Upon a base or stand 1 there is erected a frame 2 throughwhich extendsthe armature shaft- 3 of the machine, the armature being indicated bydotted lines at 4, and

since it may be an armature of ordinary type, such armature needs nodescription.

The field of the motor is made of a per manent magnet 5, provision beingmade to divert part of the flow of the magnet lines of force away fromthe armature windings and core at will so as to weaken or strengthen thefield and so regulate the speed. thumb nut 6 is provided for thispurpose. Of course any other means for regulating the speed of the motormay be used it so desired. Thearmature shaft 3 carries the usualcommutator 7 engaged by brushes 8, both commutator and brushes beingshown in dotted linesand need not differ from structures of likecharacter in common use.

Upon the cnn of the shaft 3 remote from the commutator 7 is a polechanging commutator 9 comprising, in the particular structure shown inFig. 2 two overlapping members separated by insulating material 10 atthe contiguous ends. Mounted on the frame 2 are. two posts ll carryingbrush holders 12 each of which is formed with a binding post 13 for theattachment of electric conductors to each brush holder 12. These brushholders may be arranged in the same vertical plane with one pairdiametrically opposite to the other )air, one member of one pair ofbrush holders engaging one of the members of the commutator 9continuously, and the other member of the same pair arranged to engagethe overlapping portion of the two members of the commutatoralternately.

In Fig. 2 the commutator 9 is of the drum type. This may be replaced bya disk commutator'14 shown in Figs; 3 and 4, in which case the brushholders 12 are located tov correspond to the changed shape of thecommutator. In the structure in Figs. 3 and 4 and best illustrated inFig. 4 the commutator comprises two concentric members 15 and 16 uponwhich bear brushes respectively connected to the positive and negativesides The brushes in the brush in constant engagement with the member 15and another brush in constant engagement with the member 16 while theother two brushes are so located as to engage alternately the member 15and the member 17. Conductors connected to the brushes will receiveconstant current or alternating current in accordance with the portionof the commutator 14 upon which they bear.

In the diagram of Fig. 1 there are illustrated two current sources 18and 19 which may comprise each a suitable number of battery cellsconnected up in series. These batteries may be composed of eitherprimary or secondary cells and are coupled together in sutficient numberto deliver the desired voltage, and for certain purposes it may bedesirable to use the type of battery known as the dry battery.

One side-of each battery 18 and 19 is connected to a conductor 20 andthis conductor -may be connected to another conductor 21 leading to thecentral station switch board which however is not illustrated in thedrawings. The same conductor 21 is connected to one of the brushes 12 inconstant contact with one of the members of the commutator 9. The otherside of each battery is connected one byaconductor 22 toa switchterminal 23 and the other by a conductor 24 to a switch terminal 25, theterminals 23 and 25 being individually in the path of the switch arms 26connected by a conductor 27 through a fuse 28 to one of the brushes 12in constant contact with the other member of the commutator 9. Anotherconductor 29 is connected to the conductor 27 and leads to theswitchboard which, as before stated, is not shown in the drawings. Theconductors 21 and 29 constitute the positive and negative conductorsrespectively whereby such'cur-J rent may be delivered directly to theswitchboard from either group of battery cells 18 or 19.

One of the intermediate conductors 12 is connected by a conductor 30 tothe switchboard ground and the other intermediate brush 12 is connectedby a conductor 31 to the switch board and constitutes the alternatingcurrent lead to the switch board from the commutator 9.

Let it be assumed that the motor 4 has its brushes 8 connected up byconductors 32 and 33 to the conductors 20 and 27 respectively. Now assoon as the switch arm 26 is brought into contact with either theterminal 23 or 25 there is established a circuit, assuming that theswitch arm 26 is in contact with the terminal 23, from the battery 19through the conductor 20 and through the conductor 32 to the commutator7 of the motor, the return circuit being traced through the conductor33. conductor 27, switch arm 26 by contact 23 and conductor 22 back tothe battery 19. The motor is thus energized by the current fromthebattery 19 and is caused to rotate.

The operator at the switch board now has under control a number ofcurrents of differentcharacteristics. For instance, a

steady current of the constant type may be sent by coupling to line thepositive and negative conductors 21 and 29, when the circuit may betraced from the battery 18 or 19, as the case may be, to the conductor20 and from the latter to the conductor 21 and returning by way of theconductor 29 to the conductor 27 thence by the switch 26 to theconductor 24 or 22 and back to the respective battery; or a pulsatingnegative current may be sent to line by coupling the conductor 29 to theline which is assumed to be grounded at the other end, the return beingthrough the ground conductor 30, in which case the circuit may be tracedfrom the battery through the conductor 20 to the conductor 21 and brush12 connected thereto, thence through one of the segments of thecommutator and out through the ground conductor 30, thence by way of theconductor 29, conductor 27 and switch 26 back to the battery; or apositive pulsating current may be sent to line by coupling up theconductor 21 with the return through the ground 30, in which case thecircuit may be traced from the battery through the conductor 21 to thecentral station, returning by the ground wire 30 to the commutator 9and, when the latter has turned to the proper point, from the saidcommutator to the conductor 27 and switch 26 and back to the battery,conductor 12, commutator 9, conductor 30, to the ground, returning byconductor 31 to the commutator 9, conductor 27, to the battery, thecommutator constantly reversing the current; or by coupling theconductor 31 to line an alternating current may be sent to the line withthe return through the ground 30. By providing two series of batteries18 and 19 the service need not be interrupted because of the weakeningof one battery group since'the other is available while the weakenedgroup is being renewed.

Referring now to Fig. 5 there is shown a system for furnishingalternating currents to the line without producing noises at theswitchboard and without any kickback from the main line circuit into thebattery used as the prime source of power. In this figure the battery isindicated at 34 and may if desired be of the type known as a storagebattery.- In this drawing the motor is shown simply by the armature 4and commutator 7 while the circuit controlling commutator driven by themotor is the same as the commutator shown in Fig. 1 and is in,- dicatedby the same numeral 9.

One side of the battery 34 is connected to one of the brushes 12constantly bearing emcee? upon one member of the commutator Q, theconnection being through a conductor and the same side of the battery isalso connected to ground through a conductor 36. The other side of thebattery 34 is connected by a conductor 37 to a double knife switch 38and in the path of this switch are two contacts 39 and 39 so that whenthe switch is closed onto the contacts both are simultaneously incircuit with the conductor 37.

There are two conductors 40 and 41 leading to theswitchboard and theseconductors are connected to opposite sides of the secondary winding 42of a transformer 43, the primary winding of which is indicated at 44.This transformer is properly wound to raise the potentialof currentsfurnished to it and deliver high voltage currents to the conductors 40and 41. Bridged across the terminals of the secondary 42 of thetransformer 43 is a condenser and a non-inductive resistance designatedbythe numerals 45 and 46 respectively, the said condenser andnoninductive resistance being coupled together in series but bridgedacross the conductors 40 and 41. in multiple with the secondary of thetransformer 43.

The condenser and resistance bridged across the secondary of thetransformer has been shown in practice to take up the discharge at alltimes from the transformer and to cut down the spark at the commutator.The condenser and resistance in series acts similar to a counterelectromotive force, when properly balanced with the transformer design,but is found to be much better and more economical in action and alsoconsumes less current.

The terminal 39 is connected by a conductor 47 through a fuse 48 to onebrush 8 of the commutator 7 of the motor while the other brush 8 of thiscommutator is connected by a conductor .49 to a conductor .50 leadingfrom the battery 34 at the point of junction of the conductors and 36therewith, to the conductor 41. The other terminal 39 of the switch 38is connected through a fuse 51 to one side of a retardation or chokecoil 52 by a conductor 53 and the other side of this coil 52 isconnected by a conductor 54 to one of the brushes 12 in constantcommunication with the member of the com mutator 9 other than that towhich the brush 12 connected to the conductor 35 is in constant contact.

The coil 52 is provided with two windings which may beconnected togethereither in series, or in multiple or may he used singly thus permitting achange in resistance and choking effect in the primary circuit.

The particular arrangement shown in the drawings is that of the multiplearrangement of the two windings of the coil 52.

The two brushes 12 which make alternate contact with the, respectivemembers of the commutator 9 are connected one by a. conductor 55 to oneside of the primary winding 44 of the coil 43 and the other brush by aconductor 56 to the other, side of the said primary winding 44. lVhenthe switch 38 is opened then the battery 34 will furnish no current,being on open circuit, but when the switch 38 is closed onto the twocontacts 39 and 39 there is established a circuit from the battery 34through the commutator 7 and armature 4 of the motor, thence by theconductor 47 through the fuse 48 to the terminal 39, thence by way ofthe switch 38and conductor 37 back to the battery. The current furnishedthrough this circuit will cause the rotation of the motor and the likemovement of the commutator 9. Another circuit may be traced from thebattery 34 by way of the conductor to one member of the commutator 9thence by the conductor 55 through the coil 44 returning by theconductor 56 to the othermemher of the commutator 9 thence by way of thecon ductor 54 and coil 52 to the conductor 53 and through the fuse 51 tothe terminaLor contact 40, and from thence by way of the switch 38 andconductor 37 back to the battery 34. During the rotative movement of themotor and commutator 9 this circuit is maintained except that thedirection of cur rents through the conductors 55 and 56 and the winding44 of the coil 43 is reversed at every rotation of the commutator 9.This reversal of the current through the primary winding of the coil 43will set up alternating currents in the secondary winding 42 and theline wires 40 and 41 and such currents may be utilized by an operatorfor charging a line and ringing bells responsive to such current. Ofcourse the voltageof the our rents sent to line through the conductors40 and 41' will .depend upon the relation of the turns of the coil 42 tothe turns of the coil 44 thus permittingthe sending to line of as highvoltage current as may be desired. The condenser 45 and resistance coil46 bridged across the terminals of the secondary winding 42 of the coil43 cause the transformer to discharge through the secondarv and thismakes a perfectdischarge with each and every reversal of the currentandv the ringing of the, bells controlled bv the current thus furnishedis clearer and more pronounced t-han with other designs. The path ofdischarge furnished by the condenser and coil on the secondary side ofthe transformer 43 prevents the kickback into the batterv and keeps theswitchboardfrce from ringing induction.

In the arrangement shown in Fig. 0 there are provided two motor drivencommutator: 9 and two transformers 43 while for the energization of thecircuit and the dri ing ofthe motors but one current source 34 isrequired, although this does not preclude the use of more than onecurrent source if desired.

From one side'of the current source 34: which latter may be either aprimary or a secondary battery, there leads a conductor 57 including afuse 58 and which terminates at a switch 59 having two sets'of switcharms 60 and 61, the conductor 57 being common to one switch arm 60 of apair of switch arms and to an adjacent switch arm 61 of the other pairof switch arms. The other two adjacent switch arms 60 and 61 areconnected by a conductor 62 to an adjustable choke coil 52 the otherside of which is connected by a conductor 63 to the conductor 57. In thepath of one of the switch arms'60 is a terminal 64 from which leads aconductor 65 to one of the brushes 8 of the commutator 7 of one of themotors. The other brush 8 of the commutator 7 is connected by aconductor 66 to a conductor 67 connected to the-side of the battery 84remote from the conductor 57; The other switch arm 60 of the switch 59has in its path a circuit terminal 68 connected by a conductor 69 to oneof the brushes 12in constant engagement with one of the'members of thecommutator 9.

One of the switch arms 61 of the switch 59 has in its path a circuitterminal 70 while the other switch arm 61 has in its path a circuitterminal 71. The. circuit terminal 70 is connected by a conductor 72 toone of the brushes 8 of the commutator 7 of the other motor while theother brush of this motor is connected by a conductor 73 to theconductor 67 before referred to. The other terminal 71 is connected by aconductor 7 4 to one of the brushes 12 in constant engagement with amember of the commutator 9 driven by the second motor.

The conductor 67 is connected by a conductor 75 to the brush 12 inconstant engagement with the other member of thecommutator 9 of thefirst named motor and the conductor 67 is itself also connected to thebrush 12 in constant engagement with the other member of the commutator9 of the second named motor from that with which the conductor 74 isconnected.

One of the brushes-12 which are arranged to make alternate contact withthe two members oi the commutator 9 of the first named motor isconnected by a conductor 76 to a circuit terminal 77in the path of aswitch arm 78 'of a switch 79 and also in the path of the switch arm 78is another circuit terminal 80 connected by a conductor 81 to the brush12 of the commutator 9 of the sec ond motor corresponding to the brush12 of the first named motor to which the conductor 76 is connected.

The switch 79 is provided with another switch arm 82 in the path ofwhich are two terminals 83 and 84. The terminal 83 is connected by aconductor 85 to the contact brush of the commutator 9 of the first namedmotor opposite that to which the conductor 76 is connected. The contactterminal 81 is connected by a conductor 86 to the corresponding brush 12of the commutator 9 of the second named motor to that brush of thecommutator 9 of the first named motor to which the conductor 85 isconnected. There is also provided another switch 87 having two sets ofarms 88 and 89 similar to the switch 59. The arm 78 ofthe switch 79 ispermanently connected to the arms 88 and 89 on one side of the switch 87by a conductor 90 while the arm 82 of the switch 79 is connected by aconductor 91 to the other arms 88 and 89 of the switch 87.

In the path of the two arms 88 of the switch 87 are two circuitterminals 92 and 93 connected by respective conductors 91 and 95 to theprimary winding -14 of the transformer 43. In the path of the arms 89 ofthe switch 87 are other contacts 96 and 97 connected by respectiveconductors 98 and 99 to the primary winding 41 of another transformer43. 1

Bridged across the secondary windings 12 of each transformer is acondenser 15 and a non-inductive resistance 4:6 in series one with theother. One side of each secondary winding 12 of the two transformers 43is connected to a conductor 100 leading to the switchboard or to ringingbus-bars which however are not shown and may be such as are in ordinaryuse. The other sides of the secondary coils of the two transformers 43are connected by respective conductors 101 and 102 to respective circuitterminals 108 and 104. The circuit terminal 103 is in the path of aswitch arm and the circuit terminal 104 is in the path of the switch arm106 and these two switch arms 105 and 106 have common connection to aconductor 107 leading to the switchboard or to the ringing bus-bars.

"With the arrangement shown in Fig. 6 either side of the switch 59 maybe closed down on the respective contact and in that case either motorwill be energized or both motors may be charged at the same time. By aproper manipulation of the two mem-- bers of the switch 87 either orboth transformers +13 may be coupled to the switch 79 at will. Howeverthe commutators ot' the two motors may be coupled up to the switch 87only one at a time. Furthermore, the secondaries of the two transformersmay be coupled up singly or together in multiple arc relation to theline conductors 100 and 107 by a propermanipulation of the switch arms105 and 106.

The circuits may be traced as follows: from the battery 31 by conductor57 thence to switch 59 and by way of conductor 65 to owes? thecommutator9, thence by conductor 66 to conductor 67 and back to thebattery 84', considering the switch 59 as closed on the conductor 65. Itthe other side of the switch 59 be closed on the conductor 72 then theother motor will be energized, or if both switches be closed then bothmotors will run.

Considering the commutator 9 the circuit may be traced from the battery3 1 to the conductor 57 to the conductor 63, through the inductors 52and from thence by the conductor 62 to the switch 59, thence to theconductors 69 and 74 and to the respective commutator 9. Under theshowing of the drawings the circuit may be continued from /onecommutator through the conductor 7 6 to theswitch 79, if the latter beclosed thereon, thence byway of the conductor 90 to the switch 87, and,if the latter be closed on the contact 97, then by wa of the conductor99 through the primary 0 the respective induction coil thence by way ofthe conductor 98 again to the switch 87 on the other side thereof,thence by conductor 91 to the switch 79and, assuming that the latter isclosed on the contact 88, from the said contact 83 to the conductor 85,thence through the respective segment of the commutator 9 by way ofconductor 75 to conductor 67 and back to the battery 34. The circuit onthe other side of the system shown in Fig. 6 is like that just describedand so need not be repeated.

As the commutator 9 rotates, first a positive impulse and then anegative impulse will traverse the circuit and the transformer will becharged in the usual manner sending alternating currents to the lineconductors 100 and 107.

By running the motors at different speeds it is within the power of theoperator to throw upon the line currents of correspondingly dlfferentfrequency while complete control over the current produced upon the line100 and 107 and also as to whether one or the other or both motors shallbe operating is provided by the several switches 59, 79, 87, and 105 and106. I

The diagram in Fig. 7 illustrates a system similar to that of Fig. 6 butincluding means for sending pulsating currents to line for ringingpurposes.

The two motors and two transformers are retained and also the currentsource represented by the batter 341 as well as the retardation or chokecoi 52 and the switch 59.

The commutators 9 are however replaced by other commutators 9 differingfrom the commutators '9 in having a segment or member intermediate ofand overlapping the two end members which are separated by theintermediate member. The conductor 65 is connected to the commutator 7of the motor as in the arrangement shown in Fig. 6 and the conductor 72is connected to the commutator '4" of the other motor as in Fig.

6. The conductor 69 is connected to a brush 12 of the commutator 9 ofone motor which brush is in constant engagement with one of the endsections of said commutator. The conductor 7 4C is connected to a likebrush 12 of the commutator 9 of the other motor. There is also providedanother switch 108 provided with four switch arms 109, 110, 111, and 112insulated one from the other but connected for simultaneous control.There is also provided still another switch 113, having two sets of arms114: and 115, the several arms 114 being insulated one from the otherand connected for simultaneous control and the same is true of the arms115.

In the path of the switch arm 109 are two circuit terminals 116 and 117.In the path of the switch arm 110 are two circuit terminals 118 and 119.In the path of the switch arm 111 are two circuit terminals 120 and 121.In the path of the switch arm 112 are two circuit terminals 122 and 123.

-.The circuit terminal 116 is connected by a conductor 124 to one of thebrushes 12 of the commutator 9 of the first named motor which brush isin constant engagement with the end member of the commutator -9 remotefrom the member with which the conductor 69 is in constant engagement.The circuit terminal 117 is connected by a conductor 125 to a. contactbrush 12' similar in arrangement to the commutator 9 of the second namedmotor as is the brush of the commutator of the first named motorconnected to the conductor 124C. The contact terminal 118 is connected.by a conductor 126 to a. contact brush 12-of the commutator 9 of thefirst named motor arranged to make alternate contact with theintermediate member of the commutator 9 of the first named motor and theend member with which the conductor 12 1 makes constant contact. Thecircuit terminal 119 is connected by a conductor 127 to al brush 12 ofthe commutator 9 of the second namedllO motor corresponding to theconnection of .the conductor 126 to the first named motor.

The circuit terminal 120 is connected by a conductor 128 to a contactbrush 12 in constant engagement with that segment of the comn'lutator 9of the first named motor with which the conductor 69 is in constantengagement. The contact 121 is connected by a conductor 129 in a similarmanner to a brush 12 in constant engagement with the commutator 9 of thesecond named motor, this being the same segment with which the conductor74 is in constant engagement. T he circuit terminal 122 is connected bya conductor 130 to a brush 12 in position to 125 engage alternately withthe intermediate member of the commutator 9 of the first named motor andthe end member with which the conductors G9 and 128 are in constantengagement. The circuit terminal 128 is connected by a conductor 131with a brush 12 related to the commutator 9 of the second named motorsimilar to the brush of the commutator of the first named motor to whichthe conductor 130 is connected. 1n the path of the arms 114 of theswitch 113 are circuit terminals 132, 133 and 134 and in the paths ofthe arms 115 of the switch 113 are other circuit terminals 135, 136 and137.

The circuit terminal 132 is connected bya conductor 138 to one side ofthe secondary winding 42 of one of the transformers The circuit terminal133 is connected by a conductor 139 to one side of the primary windingof the transformer43 referred to. The circuit terminal 134 is connectedby a conductor 140 to the other side of the primary winding 44 of thetransformer 43 referred to. The circuit terminal 135 is connected by aconductor 141 to one side of the secondary winding of the secondtransformer 43. The circuit terminal 136 is connected by a conductor 142to one side of the primary winding 44 of the second named transformer.The circuit terminal 137 is connected by a conductor 143 to the otherside of the primary winding of the second transformer.

The switch arms of the switch 113 in the paths of which are the circuitterminals 134 and 137 are connected by a conductor 144 to the switch arm112. The switch arms of the switch 113 in the paths of which are thecircuit terminals 132 and 135 are also con nected to another switch arm145 in the path of which are two circuit terminals 146 and 147. Thecircuit terminal 146 is connected by a conductor 148 to a brush 12' ofthe commutator 9 of the first named motor in constant engagement withthat end of the said commutator with which the brush con: nected to thebrush 124 is'also in constant engagement. The contact circuit terminal147 is connected by a conductor 149'to a brush 12 of the commutator 9 ofthe other motor corresponding to the brush with which the conductor 148is connected.

In the diagram of Fig. 7 there are shown four line wires or conductors150, 151, 152 and 153. It will be observed that these conductorsareshown in dotted lines, but this is oniliy for distinctive purposesand to clearly di erentiate these conductors from other conductors.

The conductor 150 is coupled to the side of the secondary winding of thefirst named transformer remote from that to which the conductor 138 isconnected, and the secondary'winding of the other transformer isconnected to this same conduct-or on the'side remote from that to whichthe conductor 141 is connected. The conductor 151 is connected to theswitch arm 145 and also to the switch arms 114 and 115' in the paths ofwhich are the circuit terminals 132 and 135. The conductor 152 isconnected to the switch arm 109 and conductor 153 is connected to theswitch arm 110.

As already explained with relation to the system of Fig. 6 either orboth motors may be set in operation by a suitable manipulation of theswitch 59, and at the same time either or both conductors 69 and 74 arecoupled up to the current source.

The switch arms 109, 110, 111, and 112 of the switch 108 can be broughtinto engagement with the circuit terminals 116, 118, 120 and 122 or withthe switch terminals 117 119, 121 and 123 but only with one set at atime.

The switch 113 may be manipulated to bring the switch arms 114 intoengagement with the circuit terminals 132, 133 and 134 and the switcharms 115 into engagement with the circuit terminals 135, 136 and 137 thesaid switch arms 114 and 115 being capable of manipulation to elose thecircuit onto their respective circuitterminals at the same time if theoperator so wills.

The switch arm 145 may be brought into contact with either circuitterminal 146 or 147 but not both at the same time.

Let it be assumed that both members of the switch 59 are closed and bothmembers of the switch 113 are also closed, and that the switch 108 isclosed onto the circuit terminals 116, 118, 120 and 122. Furthermore letit .be assumed that the switch arm 145 is closed on the contact orcircuit terminal 146. There is now transmitted to the conductors 150 and151 alternating currents from the secondary of the first namedtransformer 43 while pulsating currents are sent to the conductors 152and 153, the frequency of these currents depending upon the speed of thecommutator 9 of the first motor. By reversing the switch 108 and alsothe switch 145 the second commutator 9 may be brought into action andcurrents of av the quency depending upon the speed of rotation of thiscommutator will be sent to line as before.

The circuits of Fig. 7 may be traced asfollows: Leaving the battery 34the circuit may be traced along the conductor 57 to the switch 59 thenceby conductor 65 to the motor 4 and returning by conductor 66 toconductor 67 and back to the battery34. Another circuit'may be tracedfrom the bat- 1 0 tery 34 by way of conductors 57 and 63 through thereaction coil 52 thence by conductor 62 to the switch 59 thence byconductor-69 to the commutator 9' on the left hand side of the figurethence by conductor 12 128 to the terminal thence by switch arm 111 andby conductor 120. to the switch 113, thence to contact 133 and to theprimary coil of the transformer at the left hand side of Fig. 7. Fromthis transformer thecir- 1 cuit may be traced by conductor 140 tocontact 134, thence by the switch 113 to the conductor 144, thence toswitch arm 112, contact- 122, conductor 130, to the central block of thecommutator 9 first considered, thence to conductor 6'7 and back" to thebattery. Another circuit may be traced from the commutator 9' by way ofthe conductor 126 to the terminal 118,- switch arm 110, and by conductor 153 to the switch board. mutator 9 rotates'the transformer willreceive alternating currents and deliver other alternating currents tothe conductors 150 and 151.

In Fig. 8 there is shown the system of Fi n- 5 with the addition ofmeans for producing pulsating currents in addition to the alternatingcurrents. For this purpose the commutator 9 is used instead of thecommuta tor The battery 3% is connected by the conduotor to brush 12' inconstant contact with the intermediate member oi the comniutator 9. Thisintermediate member takesthe place of one of the end members of thecommutator shown in Fig. 5. The alternating side or? the system of 8 islike that of Fig. 5 and. requires no further de scription.

There are other line conductors 154 and 155. The conductor 154i isconnected to a brush 12 arranged to engage alternately the end member ofthe commutator 9, remote from that engaged by the brush connected to theconductor and also to engage the intermediate member or the commutator9. The conductor 155 is connected to a brush 1% which like the brushconnected to the conductor 154s is designed to alternately engage theintermediate member of the commutator 9 and that end member which isengaged by the brush connected to the conductor 154. However since thesetwo brushes are in opposite relation one to the other they are never inengagement with the samemember of the commutator at the same time. Theend member of the commutator 9 remote from that engaged by the brushconnected to the conductor 54:: is engaged by a brush 12 connected by ticonductor 156 to one side of the secondary winding 4-2 of thetranstormer 4-3.

With the system shown in Fig. 8 the switch is closed to set the motor inoperation and then alternating currents are pro duced upon the lines 40,at and pulsating currents upon the lines lot and 155 the pulsatingcurrents being positive or negative upon the conductors i154 and 155 inaccordance with the connection of these conductors to the battery 84-.

The circuits shown in la ig. 8 may be traced as follows. Starting fromthe battery 34*; the current will flow through the motor t, then byconductor t? and fuse 48 to the its the comprimary of the inductioncoil.

switch 38, assuming the latter to be closed, then by conductor 37 backto the battery 34:,

thereby causing the motor to run and the commutator 9 will be actuatedthereby. In the particular position of the commutator shown in Fig. 8the circuit may be traced from the battery 3% by way of conductor 35 tothe middle segment of the commutator. thence by conductor 55 to theprimary coil or the transformer, thence bythe conductor 56 to one endsegment of the commutator. thence by conductor 5a, choke coil couductor53, fuse 51, contact at), switch 38, and conductor 37 back tothe battery3st, thus sending animpulse in one direction to the As soon as thecommutator has turned sutliciently then the relation of the conductorsand 56 has changed so that a currentimpulse will flow from the battery3% through the conductor 35thence directly to the conductor 56 and tothe primary coil ot the induction coil. thence by way of conductor 55 tothe end segment of the commutator first considered. thence by conductor54, choke coil 52. con doctor 53, and switch 38. to the conductor 3'?and back into the battery 3%, thussenth ing an impulse in the reversedirection to the primary oi the induction coil. There is therefore setup in the secondary of the induction coil a series of alternatingimpulses which may pass by the conductors 4.0 and ll to theswitch-board, or by the conductor 40 to the switch-board or other pointof utilization and back by the ground conductor 36 and conductor to theother side ot the secondary of the induction coil.

A. second impulse may traverse the conductor 156 to the other endsegment of the commutator and from thence to the switch board throughthe conductor 154, such impulses being intermittent and always in thesame direction. the the turning of the commutator the conductor 156 willbe coupled up'With the conductor 155 and an impulse of the opposite signwill be sent through this conductor to the switch-board, the impulsesbeing intermittent and always of the same opposite sign through theconductor 155. The return of the secondary winding of the induction coilmay be through the ground conductor 36 thence by the conductor 50 andthat portion of the conductor ll included between the conductor 50 andthe secondary winding of the induction coil or the return to thesecondary of the induction coil may be through the entire extent of theconductor 4:1 from the point of utilization.

lln Fig. 9 there is shown diagrammatic representation of a harmonicringing machine; Tn the arrangement shown in Fig. 9 the commutator ismade up of a number of sections 157, 158, 159, 1.60 and 161. althoughthe number or? sections be greater or smaller as desired. Forconvenience it will be assumed that the speed of rotation of the f Thesecondary windings 42 of each induceommutator and the arrangement of thesec sections 157 and 158 will deliver 16%- alternawill deliver 00 3 willdeliver 66 alternations per second. It will be observed that the meetingends of the several sections intermesh but are separated by insulatingmaterial to prevent electrical contact. On opposite sides of thecommutator bear brushes 162 in position to engage the intermeshingportions of the sections.

One side of the battery 34 is connected by two conductors 163 and 164 tothe respective arms of a double arm switch 165 and in the path of thearms of this switch are circuit terminals 166 and 167. The circuittenninal 166 is connected by a conductor 168 to a retardation or chokecoil 52 and includes a fuse 169. The other side of the choke coil 52 isconnected by a conductor 170 to a brush 171 in constant engagement withthe commutator member 159.

The circuit terminal 167 is connected by a conductor 17 2 to one brush 8of the commutator 7 of a motor such as has been heretofore described fordriving the pole changing commutator made up of the segments 157, 158,159, 160 and 161. The other brush 8 of the commutator 7 is connected bya conductor 173 to the side of the battery 34 remote from that connectedto the conductors 163 and 164. The same side of the battery.to which theconductor 173 is connected is also connected by a conductor 174 to abrush 175 in constant engagement with the commutator member 158 and thissame side of the battery is also connected to ground through a conductor176.

The commutator member 157 is permanently connected to the commutatormember 159 by a conductor 176 and the commutator member 159 ispermanently connected to the member 161 by 'a conductor 177, thus themembers 157, 159 and 161 are in constant electrical connection. Thecommutator member 158 is permanently connected to the commutator member160 by a conductor 178. The conductors 176, 177 and 178 are onlydiagrammatically represented in the drawings but it will be understoodthat in practice these conductors will be concealed within the interiorof the commutator.

It will be observed that there are four brushes 162 on each side of thecommutator.

All the brushes 162 on one side of the com tion coil is connected torespective line contions is such that brushes engaging with the j.ductors 179 and 180 and these conductors are bridged by a condenser 45and non-intions per second, the sections 158 and 159 1 alternations persecond, the i sections 159 and 160 will deliver 50 alternations persecond and the sections 160 and 161 ductive resistance 46 connected inseries adjacent to each secondary winding 42.

When the switch 165 is closed onto the circuit terminals 166 and 167 themotor is set in motion and the pole changing commutator partici )ates insuch movement. Current passes -rom the battery 34 by the conductor 164through the respectiveside of the switch 165 to the conductor 168, andfrom this conductor 168 the circuit may be traced through the fuse 169and adjustable retardation or choke coil 52 by the conductor 170 to thebrush 171 bearing on the commutator member 159. The circuit from theother side of the battery 34 may be traced by the conductor 174 to thebrush 175 hearing on the commutator member 158.

If it be assumed that the brush 171 is connccted to the positive side ofthe battery 34 then the brush 17 is connected to the negative side ofsuch battery. The circuit from the battery 34 may be traced by way ofthe conductor 164 and switch 165 to the conductor 168, assuming theswitch to be closed. thence to brush 171 and to section 159 of thecommutator, thence by conductor 17 7 to section 161 of the commutatorand from the latter by way of the brush 162 to the primary of therespective one of the induction coils, thence by way of conductor 181 toa brush 162 and to section 160 of the com lnutator, thence by conductor178 to' section 158 of the commutator and thence by Way of brush 175 andconductor 174 back to the battery. Under these conditions the circuitmay be further traced through the severa brushes 162 on the same side ofthe pole changing commutator as is the brush 171 to one side of each ofthe primary coils of the several transformers 43, the circuit returningby conductors 181 tothe brushes 162 on the opposite side of the polechanging commutator. As the said pole changing commutator is rotated therelation of the polar ends of the battery 34 to the primary Wind ings 44is alternated a number of times per revolution of the pole changingcommutator depending upon the number of intermeshing portions of themembers picking up such commutator. In the particular arrangement underconsideration it is assumed that if the number of alternations persecond between the brushes bearing upon the commutator members 157 and158 is 16% times per second then the number of alternations of the otherbrushes and primary coils will increase in the-ratio of 2, 3 and 4toward the other end of the commutator. These ratios are to be taken asexamples and the invention is by no means bound to them. HoweverWhatever ratios of alternation be chosen they cancer remain absolutelyfixed since the several members of the commutator are mounted upon thesame shaft and have the same speed of rotation at all times. By means ofthe system displayed in Fig. 9 the ringing circuits are assumed to beresponsive to the several frequencies produced upon the line.

Instead of the drum shaped commutator shown in Fig. 9, a disk commutatorsuch as shown in Fig. 10 may be used wherein there are provided twoconcentric rings 182 and 183 around which are annuli 184, 185, 186 and18'? concentric With the axis of rotation of the commutator andinsulated one from the other and from the rings 182 and 183. The severalannuli are divided into a number of sections so as to produce therequisite number of alternations in the electric current as may bedesired. The adjacent ends of the sections of each annulus are separatedby insulating material 188. The Width of the insulation 188 issuiiicient to prevent the brushes from bridging the contiguous ends ofthe sections of thedifierent annuli.

What is claimed is:-

1. in ringing system for telephone lines, a source of direct current, arotatable pole changer, a direct current motor for driving the polechanger, means for coupling the source of current to the motor and atthe same time to the pole changer and through the latter to the lineconductors, and a transformer coupled to the source of current throughthe pole changer.

2. ln a ringing system for telephone lines, asource of constant current,a rotatable pole changer, a constant current motor for driving the polechanger, means for coupling the source of current to the motor and atthe same time to the pole changer and through the latter to the lineconductors, a transformer coupled to the source of current through thepole changer, and a condenser and resistance in series bridged acrossthe secondary Winding of the transformer.

S. In a ringing system for telephone lines, a source of constantcurrent, a rotatable pole changer, a constant current motor for drivingthe pole changer, means for coupling the source of current to the motorand at the same time to the pole changer and through the latter to theline conductors, a transformer coupled to the source of constant currentthrough the pole changer, and a condenser and a non-inductive resistancein series bridged across the secondary Winding of the transformer.

4. ln a ringing system for telephone lines, a source of constantcurrent, a rotatable pole changer, a constant current motor for drivingthe pole changer, an adjustable retards tion or choke coil in thecircuit of the pole changer, a transformer for converting the currentsupplied by the constant current source into alternating current, and acondenser and resistance in series bridged across the secondary of thetransformer.

5. In a ringing system for telephone lines, a source of constantcurrent, a rotatable ole changer, a constant current motor for urivingthe pole changer, an adjustable retardation or choke coil in the circuitof the pole changer, a transformer for converting the current suppliedby the constant current source into alternating currents, and acondenser and non-inductive resistance in series bridged across thesecondary of the transformer.

6. In a ringing system for telephone lines, a source ct constantcurrent, a rotatable pole changer, a constant current motor for drivingthe pole changer, a retardation orchoke coil in the circuit of the polechan er, said retardation coil having two "Win ings, a transformer forconverting the current supplied by the constant current source int-oalternating current, and a condenser and resistance in series bridgedacross the secondcry of the transformer.

'Z. in a ringing system for telephone lines, a source of constantcurrent, a rotatable pole changer, a constant current motor for drivingthe pole changer, a retardation or choke coil in the circuit of the polechanger, said retardation coil having two windings, a transformer forconverting the current supplied by the constant current source intoalternating currents, and a condenser and non-inductive resistance inseries bridged across the secondary of the transformer.

' In testimony that I claim the foregoing as my own, I have heretoaffixed my signature in the presence of two Witnesses.

WILLIAM E. BUTLER.

Witnesses:

W ILMAM E. HEWIT, J. K. Mesmrrr.

